Initial velocity at t = 5 s
[tex]v = 1.5 \hat j[/tex]
final velocity at t = 10 s
[tex]v = -1.5 \hat i[/tex]
so the time taken by the object to revolve by 270 degree is t = 10 - 5 = 5s
so here we can find the angular speed
[tex]\omega = \frac{\theta}{t}[/tex]
[tex]\omega = \frac{\frac{3\pi}{2}}{5}[/tex]
[tex]\omega = 0.94 rad/s[/tex]
now we know that
[tex]v = R\omega[/tex]
[tex]1.5 = 0.94 * R[/tex]
[tex]R = 1.59 [/tex]
so the coordinates of the center will be
[tex]x = 4 + 1.6 = 5.6 m[/tex]
[tex]y = 3 m[/tex]
so the coordinates of center is (5.6 m,3 m)